Police acting on a tip found seven bodies partially buried in the desert on the outskirts of the Mexican border city of Ciudad Juarez, an official said Saturday.
Investigators are searching the desert site south of the city to see whether there are any more bodies.
An official with the state prosecutor's office who declined to be named in line with department policy says a police officer's badge was found at the site. Authorities were working to identify the bodies.
Ciudad Juarez, across the border from El Paso, Texas, has been hit by a wave of drug-fueled violence that led federal authorities to dispatch thousands of soldiers to patrol the city.
State security official Enrique Torres Valadez said that 1,500 more troops are expected to arrive Saturday, and 2,150 arrived Friday.
Also Saturday, a suspect threw a hand grenade at police officers in the western city of Guadalajara. The officers were not seriously injured.
State prosecutors said in a statement that police searched the man's home and found 14 more grenades and 10 assault rifles.